I am curious if the wire bundle and pass through point were the issue. I have a 1998 4Runner with the notorious passenger side dash rattle. It sounds like it is coming from the passenger side airbag zone. I have removed the glove box and I could not get up inside of the dash. The airbag is sealed off with a plate cover from below. The rattle kicks in at 60 mph on freeway or when going over large bumps.